


A Void As Clear As Black

by Corporal_Dropkick



Category: Undertale (Video Game), 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Angst, Chara and Asriel Grew up to become Pro Heroes, Graphic Depictions of Cybernetics, Graphic Depictions of things in general, Graphic depictions of violence - Freeform, Humor, Izuku has a Determination Soul, Izuku learns Magic, Midoriya and Bakugou don't hate each other, Other, PTSD Gaster, Post-Glitchtale, Slow Burn, Some Fluff, Some death, Teen Romance (Maybe?), Violence
Language: English
Status: In-Progress
Published: 2020-11-09
Updated: 2020-11-09
Packaged: 2021-03-09 01:27:48
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 2,892
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27462691
Author URL: https://archiveofourown.org/users/Corporal_Dropkick/pseuds/Corporal_Dropkick
Summary: Izuku Midoriya was told that day that he couldn’t be a hero. Things change however, when a mysterious stranger sees something that has laid dormant for a long time in Izuku’s soul, and soon there’s a chance yet that Izuku Midoriya can in fact become a hero.But not all things are sunshine and rainbows, and Izuku learns that with his newfound powers, comes a whole new world, and a whole new plethora of enemies.
Relationships: I don't know I'm really new to this, I don't plan to do any shipping at the current moment, Relationships to be determined in the future
Comments: 4
Kudos: 22





	1. A Heroic Determination

**Author's Note:**

> Spoilers for “Undertale” and the Web Animation “Glitchtale”. If you haven’t played the game or watched the Animation before, go do so, and you can avoid the spoils unless you don't care about spoilers. That’s all I got to say.

Today was just the worst day ever. 

  
At least, that’s what it felt like for one Izuku Midoriya.  
The green haired boy sighed as he made his way back home.

Encountering All Might had been sheer dumb luck on his part, and yet the conversation that arose from that encounter was disheartening to say the least.

All Might had told him that if he was Quirkless, it just wasn’t possible for him to be a hero. That he should seek out a job as a police officer, and it was too dangerous for a quirkless kid to become a hero.

Izuku turned his gaze towards the darkening rain-filled sky, reflecting on the revelations All Might had given him. He was still shell-shocked that the greatest hero was crippled, not unlike Izuku himself in a way. He knew full well what it was like to have to deal with a weak body and Izuku respected All Might even more for continuing to do hero work despite his disability.

But it still stung when All Might told him that he couldn’t become a hero without a Quirk.

He closed his eyes. He knew the answer, and he knew he shouldn’t have asked. He was stupid to have asked All Might, the number one hero, such a thing. He should have just let it stay...

Knowing that still didn’t make it hurt any less, and it still didn’t make Izuku feel any better.

There was an uproar from a nearby street that grabbed his attention. He blinked and approached the crowd, trying to figure out what was going on. He spotted several heroes keeping the crowd back, away from a huge fire and a writhing mass that looked disturbingly similar to-

Izuku stared in horrified disbelief.

There, sitting in the middle of the street...

It was the Sludge villain that had tried to possess his body earlier! The one All Might had captured!

But wait, how, why?

_He must have escaped somehow when I was nagging All Might,_ Izuku realized.

Guilt swelled up in him until he almost felt sick. _This is all my fault! Dammit!  
_

“Everyone stay back!” That was Kamui Woods, shouting at the crowd. “The villain has taken a hostage! Please back away and remain calm!”

That must’ve been why the heroes weren’t fighting the villain, Izuku realized as he worked his way to the front of the crowd to see better. Some of the heroes around him were doing their best to put out the flames raging in the street, but they couldn’t approach the villain himself. The destruction that was about was very harsh, cars overturned, and rubble all over the place...

It was like he was staring at a walking disaster.

The villain suddenly turned so that Izuku had a clear line of sight to the hostage’s face.

Revealing that who he had in his grip was in fact one Katsuki Bakugou. 

Katsuki had never been the best of people, but they had known each other since they were in Kindergarten, and perhaps even before. Their moms had been good friends, so it only made sense they knew each other in some regard. They were friends, and Katsuki always had an air of constant bravery ahead of him.

Things took a turn though, when Katsuki took to picking on him in their elementary and middle school years after he got his super powerful quirk... But Izuku still held onto the hope that maybe Katsuki could change for the better. That maybe he could be the same hope filled individual that loved heroes as much as he did.  
Maybe he could find a small bit of that kindness that once filled his heart when they were younger.

But seeing him right now, His eyes were wide in terror as the Sludge Villain tried to claw his way into Bakugou’s mouth. Izuku felt terrible. This was all his fault...

But he couldn't just sit there and do nothing.

Before he even realized what he was doing, Izuku bolted past the heroes and straight towards the villain. His soul started to burn. Burning brighter and brighter than ever before. A sheer red determination burning in his heart and resonating in his soul.

“Wha- HEY!” Kamui Woods roared after him. “Get back here! Are you insane?!”

Izuku ignored him. He had the Sludge villain’s attention now, and he certainly recognized Izuku from before if the flash of anger in his shifting dirty eyes said anything. The villain forced Katsuki’s body to move, contorting his limbs and palms, causing several explosions to burst out in Izuku’s general direction.

Before he knew what he was doing, Izuku started to charge at the sludge villain as an energy in his soul started to manifest. Before he knew it, a red shield manifested itself in front of Izuku’s arm,and the explosive energy pinged and bounced off of the shield as Izuku kept charging forwards in a desperate attempt to save his childhood friend. The villain managed to blurt out a surprised “What the hell” before Izuku charged straight into the pile of sludge.

The impact sent shockwaves rippling through the sludge villain as his grip on Bakugou slipped. Red energy crackled from Izuku’s chest as he gasped and held his shield in front of him.

“Deku!” Katsuki managed to gasp out, glaring in bewildered fury at his classmate. “Just what the hell was that?! And what are you doing here?!”

“I came to save you! I couldn't just stand there and watch you die!” Izuku screamed.

“Dammit you nerd get lost!” Katsuki roared back. “You’ll get yourself killed!”

“You stinking little brat!” The villain snarled, forming a huge fist of sludge to pulverize him with. 

“Die already!”

The sludge soon impacted against Izuku’s shield. As powerful as the shield had been with the first impact, it's power was starting to wane as the sludge villain's slime pounded and pounded against the shield. It started to crack, before the villain reared back and slammed Izuku with the sludge of his body, breaking the shield upon impact.

‘Oh no, I’m gonna die now…’

But Izuku didn't much to the surprise of the Sludge Villain. A red energy crackled around Izuku's body as the slime impacted, and caused red to flare all over his body. It hurt the sludge villain, but hurt Izuku more as the impact sent Izuku flying backwards.

In the crowd behind all of this, All Might lunged forward in his muscle form.

He couldn’t ignore what Izuku had just done. He was already kicking himself for letting the villain escape and now this boy had taken it upon himself to act when no one else- including himself- had done a thing. He felt so ashamed of himself that his deteriorating condition flew to the back of his mind so that he could save the two boys before him. Nothing else mattered.

He rushed forwards, and grabbed Izuku, and setting him down on the sidewalk gently. 

“You’ve done well, now let me show you how a real hero does things!” 

All Might wound up a punch, before punching with all of his might forwards, his soul shining a bright purple.

“DETROIIIT SMASH!!!!” 

From the crowd, a man dressed in a black long coat watched with glowing white eyes. All Might's soul returned to his body from his sight, and he kept staring at the boy with a red soul. He smiled for once in a long while. It had been a very long while since he’d seen a soul of Determination. Chara was the last soul of Determination that he had seen in a long time, and now seeing this kid with that same trait take after the kid so much… and being so willing to put his life on the line for others...

This would prove to be very… very… interesting. 

It started to rain, as the man simply strolled away from the fight.  
This wasn't his battle anymore. But he knew he just had to talk to that kid.  
A war long thought forgotten by the humans of this world was coming again...

And he knew for a fact that this boy... and his shining soul of Determination...  
He was the key to the end of the war.

* * *

Izuku was quiet on his way back to his apartment.  
He had just witnessed something incredulous, and terrifying.   
All Might had saved him again. And now he couldn’t ever think of what else to do.

Following a quick medical checkup to make sure he was alright and a brief chewing out from some of the heroes, he was dismissed and allowed to go home. 

None of that really bothered him since Katsuki had ended up being alright as well— that was obvious enough when the boy yelled at Izuku for being stupid and jumping into a dangerous situation. 

Katsuki also gave him a rather long and heated rant about why the hell he was deciding to use his quirk now, and why he had been hiding it from him. Izuku looked down at his hands, because even he really didn’t know what he had just done.  
He just acted, and the power came flowing into him. Like a primal calling, or inherent willpower of sorts. 

He didn’t know how it happened, just that it did. 

As he approached the suburbs leading to his apartment complex, Izuku was stopped by a tall figure with a flowing coat behind them. The man approached Izuku, tired eyes wandering before settling on the meek boy’s frame. 

To Izuku, the man looked absolutely terrifying, and Izuku didn’t recognize him from any logs of Heroics or news reports…

Was he a hero he hadn’t hear about? And what was he doing here?

“Well, you certainly don’t look like it... but you are the one I’ve been looking for. I can see from your eyes that they shine brightly with Determination.” 

He extended his hand, a small grin lighting up his face. 

“Hello there, my name is Doctor Wing Din Gaster, but a lot of people prefer my surname Gaster. I am here to see you, because I believe that you are the key to save all of Monster and Human kind.” 

Izuku looked at this “Wing Din Gaster” incredulously, before the man chuckled a little. 

“Don't worry... you’ll make a fine hero Izuku, that I’m sure of. Now come with me, you have much to learn, and I have much to tell...” 


	2. Preparations

After they met, Gaster had invited Midoriya to sit with him and talk over coffee. Things just went from there.

"I believe some explanations are in order..."

Izuku shook his head before looking back to the man.

"C-can you say what you said back in that suburb again?"

Gaster looked down to the boy with a confused expression.

"Hm? Which part, the part about you being a hero or the part where I need to explain things to you?"

Izuku shook his head.

"Uh, the former part... I'm sorry, it's just... I've been told all my life that I couldn't be a hero... but hearing it from a complete stranger... well..."

Gaster nodded.

"Indeed. Well, rest assured, I know for a fact that you will make a great hero. I've seen it before, you'll do fine."

Izuku looked at Gaster with tears in his eyes, before he wiped them away, a smile on his face. Gaster's expression turned grim before he turned back to Izuku.

"Now, tell me, have you heard of the Heroes _Hyperdeath_ and _Crimson Soul ?"_

Izuku nodded and smiled.

"Of course! They were a pair of some of the first generation of heroes, and their sibling-like bond not only contributed to their popularity, but also to their teamwork! They saved so many people and defeated so many villains, that they were basically the All Mights of their generation!"

Gaster chuckled lightly to himself.

"Well, would you believe me if I told you that I used to know them? The funny thing is, they actually were siblings, and nothing could ever separate them... even after their fight against..."

He lost his words as he said that last bit.

He shook his head.

"Well, trust me when I say that I knew them, and knew them very well. In fact, I trained Hyperdeath himself in the use of many of his abilities."

Izuku shook his head incredulously.

"Wait, seriously?!"

Gaster nodded again.

"I'll tell you all about them later... for now, I need to tell you... the reason they became heroes wasn't to protect the populace from villains."

Izuku blanched for a second, before he turned back to Gaster.

"W-what? Are you serious?"

Gaster nodded.

"What they fought was an evil beyond even what you can imagine Izuku. I've fought for the past 400 years against a sentient, malevolent force called Hate."

He sighed.

"Hate manipulates people by causing them to give in to their most primal desires. Every hundred years, a soul of determination has been able to combat it and hold it at bay..."

He paused, letting it sink in for Izuku before continuing on.

"I thought that Chara and Asriel would be the ones to finally defeat Hate once and for all... even when they also had to combat a soul construct of Fear, they fought against Hate valiantly... we thought we had finally sealed it away, but it found another host that it latched itself to, and continued to feed and grow. I've seen countless heroes come and fall to Hate's clutches, and that leads me to now." 

He motioned to Izuku.

"You are this generation's soul of Determination. You may not be ready for it, but one of these days, Hate will come looking for you, and you will have to fight it. And I want you to be prepared. Which is why I will teach you how to harness the power that has lain dormant in your soul until now."

He smiled.

"I hope you are ready. We have a long way before you master your powers, and much further to go if you wish to become a hero. I hope you're ready."

Izuku nodded. He was prepared for anything. If he could become a hero, then he would do so.  
He was ready to become a hero no matter what happened.

* * *

They started off simple, Gaster focusing on Izuku's ability to call forth the power in his soul at first. While it was tricky, Izuku was finally able to manifest his soul into vague shapes and forms. It was rough, but he was able to do so.

Gaster continued with helping him focus on the supportive aspects and toolkit his soul allowed him to wield. They explored what Izuku's soul could naturally summon and form.

It wasn't entirely strong yet, but Izuku's most powerful form appeared to be a form of magic that formed shields. Gaster theorized this was because of Izuku's nature as someone who wished to protect others over hurting others. While he was able to form a sword and gauntlets of determination energy, they weren't nearly as powerful as his shields.

Gaster later found out that Izuku could also heal his targets with his soul magic. While uncommon, it wasn't entirely unheard of. Healing magic was commonly found in Kindness Souls, but could also manifest itself in other Soul traits as well.

They kept exploring Izuku's abilities and the nature of his soul as the Entrance exam creeped closer and closer.

* * *

Over the course of their training, Izuku had many questions for Gaster, one of which was how he was so old.

When asked about this, Gaster solemnly shook his head.

"Monsters do not age the same as humans do. We only age if we have children. We stop aging as soon as we hit the age of 45. As soon as we have children is when we start to continue aging. I, along with Toriel and Asgore Dreemurr, the king and queen of Monsterkind, are unfortunately unable to age anymore."

He sighs.

"I had two sons... one of them died fighting against Hate, the other... well, you should know him by his Hero name, The Great Papyrus." 

He looked off to the sun as he sighed.

"I could have changed so much...I wish I was able to in that final fight..."

* * *

"Alright... I made it..."

Izuku stopped to catch his breath as he stared at the huge building that stood at the front of U.A campus.

It had been ten months since Izuku had met that man in that suburb, and in that time he had learned so much and grew to an extraordinary degree.

Bear in mind though, he wasn't exactly the most fit. He was still very skinny and looked relatively frail.  
But looks weren't everything. And Izuku's soul burned brightly as he looked up at the main building for U.A.

Sure, his muscles were aching from waking up early to practice what he'd learned from Doctor Gaster...  
Maybe it wasn't such a good idea for him to have done so, but he needed to be ready...  
He could remember all that had happened, and thinking back on it only made him feel even more ready for what was at hand.

He was ready for U.A now.  
He was more than ready.

Seeing such an impressive building filled his heart with determination.


End file.
